// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_VIEWS_WIDGET_WIDGET_OBSERVER_H_
#define UI_VIEWS_WIDGET_WIDGET_OBSERVER_H_

#include "ui/views/views_export.h"

namespace gfx {
class Rect;
}

namespace views {

class Widget;
class View;

// Observers can listen to various events on the Widgets.
class VIEWS_EXPORT WidgetObserver {
public:
    // The closing notification is sent immediately in response to (i.e. in the
    // same call stack as) a request to close the Widget (via Close() or
    // CloseNow()).
    virtual void OnWidgetClosing(Widget* widget) { }

    // Invoked after notification is received from the event loop that the native
    // widget has been created.
    virtual void OnWidgetCreated(Widget* widget) { }

    // The destroying event occurs immediately before the widget is destroyed.
    // This typically occurs asynchronously with respect the the close request, as
    // a result of a later invocation from the event loop.
    virtual void OnWidgetDestroying(Widget* widget) { }

    // Invoked after notification is received from the event loop that the native
    // widget has been destroyed.
    virtual void OnWidgetDestroyed(Widget* widget) { }

    virtual void OnWidgetVisibilityChanging(Widget* widget, bool visible) { }

    virtual void OnWidgetVisibilityChanged(Widget* widget, bool visible) { }

    virtual void OnWidgetActivationChanged(Widget* widget, bool active) { }

    virtual void OnWidgetBoundsChanged(Widget* widget,
        const gfx::Rect& new_bounds) { }

protected:
    virtual ~WidgetObserver() { }
};

} // namespace views

#endif // UI_VIEWS_WIDGET_WIDGET_OBSERVER_H_
